Alternator question

[Scrapper]

try a new pigtail that plugs in to alt....

[C man]

Thanks for the reply..I went to the library to day and used alldata. The wire that goes from the PCM to the charging light may be grounding somewhere.Its a brown wire, I'll probably check it a the PCM end tomorrow. But I'm not going to take the whole dash apart to check it at the Instrument cluster. I wish I had a scan tool to read live parameters. I checked the pigtail connection and I'm sure its good because when I took the reading from the pigtail connection and terminal L it was steady. I also found out that the reading of 12.2v was in specs, as long as it doesn't drop below 10.6v it's okay. Thats the voltage that the PCM uses to control the alternator's field current . I can see if the Pcm is bad which I doubt since I just replaced it. By disconnected the red harness from the PCM. I will try this tomorrow. Today its to hot outside. It may be something I have to live with.

[C man]

Another ? I used my scan tool to see what voltage was the computer was seeing. It gave a reading of 13.1v but when i checked the voltage at the battery terminal I got a 14.2v reading. Is this normal? Why the big difference, because I know when It comes to cars .5v is a big difference. Is this the reason my charging light won't go off?

[HotZ28]

Which one did you check first, the battery terminal, or the scanner? And did you check at both places after the engine was idling for 2-min, or longer?

[C man]

I checked the scanner first, the battery terminal, and went back to the scanner and the reading didn't change.

[HotZ28]

Digital or analog meter on the battery?

[C man]

Its digital. I never seen an analog meter. They probably stop makin them when i was born lol. I'm only 20.

[HotZ28]

Believe it or not, you can still buy analog meters @ Radio Shack and Harbor Freight. Anyway, when you checked voltage on the scanner, did you have any accessories on?

[C man]

I tested it with the a/c on and the lights on and then I turned them off but the voltage stilled stayed at 13.1v

[C man]

I'm thinking I have a pig tail problem. The wire i kinda hard right when it comes out the pig tail connector it feels like it is broke on the inside. Could that give a slight voltage drop? I really don't want to have to cut and splice the wire but I thinking maybe thats it because when I wiggled it my scan tool lost the connection with the ECM.

[HotZ28]

Originally Posted by C man

I thinking maybe thats it because when I wiggled it my scan tool lost the connection with the ECM.

Try a new terminal (pigtail), it will not hurt to splice the wires.

[jd-autotech]

voltage regulator

[C man]

The Voltage regulator would charge at more than 14v if it was bad